This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Explore the utility of microCT as a quantiative marker for lung cancer. As part of an ongoing K08 grant we will be studying the efficacy of a number of therapies in this model of primary lung cancer, with these goals: Specific Aim 1- this project will help establish the logistical support required for the extended studies in support of this K08. More specifically the project will serve as a vehicle to work out animal transfer and IACUC for future studies. This will also provide a vehicle to streamline the gating protocols. Currently animals are intubated for scan synchronous ventilation and monitored with ECG. We propose the use of a pulse oximeter as a less invasive method that will streamline the acquisition. Specific Aim 2- previous work @ MGH has gathered reasonable image data without cardiac and respiratory gating. Our hypothesis is that the absence of this support leads to overestimation of tumor volumes. By comparing the acquisition with and without gating, we will determine specifically the impact of gating on tumor volume. This is a survival protocol and will serve as a vehicle to stress our survival support skills. Specific Aim 3 - Histologic evidence suggests that these tumors will have vascular densities of ~15% of volume. We hypothesize that a dual scan (with/without blood pool agent) will allow us to quantitate vascular density and changes in that density. This project will test that hypothesis and lay the groundwork for an R01 application. Specific Aim 4 - to this point , microPET has been considered a gold standard for detection of small tumors. We hypothesis that for the mouse, the resolution of the microCT might be sufficiently high to provide an increased level of sensitivity (and specificity) beyond that of the current gold standard. This too will provide support for a planned R01 application.